1. Field of the Invention
The present invention relates to a drive circuit for driving such a semiconductor device as a semiconductor memory device and, more particularly, to a drive circuit for supplying drive power at a predetermined voltage level to a semiconductor device of the type consuming relatively large power.
2. Description of the Prior Art
A drive circuit using a resistance type voltage divider, or potentiometer, is available for supplying power at a predetermined drive voltage level to a semiconductor memory device or similar semiconductor device. This type of prior art drive circuit is constituted by a reference voltage level generator which includes a series connection of a pair of resistors. The resistance values of the two resistors are designed in a predetermined ratio to each other. A semiconductor device is controlled by such a reference level generator. More specifically, a voltage level (e.g. +5 volts) is fed from a power source to between a reference level, or ground, of the reference level generator and one end of one of the two resistors. A drive voltage level (e.g. +4 volts) appears on a node between the resistors in association with the resistance ratio between the resistors and is applied to the semiconductor device.
In the modern semiconductor integrated circuit (IC) art, implementations for higher degrees of integration are searched for with greater keeness than before. In this respect, the prior art reference level generator, or drive circuit, should be mounted integrally with a semiconductor device which is to be driven by the reference level generator. It has already been proposed to implement by an IC a reference voltage generator which generates a regulated output voltage when supplied with an input voltage equal to or higher than a rated input voltage value from the outside and to mount such an IC integrally with a semiconductor device which uses the reference voltage generator.
However, a drive circuit of the type relying on the resistance ratio as stated above consumes inherently large power itself. Should such a driver circuit be built in a semiconductor device to play the role of an internal reference voltage generator, it would be difficult to supply a large current such as 20 to 30 milliamperes to the drive circuit due to the inherent circuit construction and, therefore, driving a semiconductor device which constitutes a heavy load would be impractical.